Telematics devices and methods for vehicle ignition detection

A method of detecting ignition events of a vehicle using a telematics device having a controller, a wireless communication module, a power input terminal configured to couple to a battery of a vehicle to sense a voltage of the battery, and an ignition input terminal configured to couple to an ignition line of the vehicle, the method comprising:

• determining whether the ignition input terminal is coupled to an ignition line of the vehicle;
• when the ignition input terminal is coupled to an ignition line of the vehicle, determining ignition turn on and ignition turn off events by detecting voltage changes on the ignition line;
• and
• when the ignition input terminal is not coupled to an ignition line of the vehicle, sensing a voltage of a battery of the vehicle to determine ignition turn on and turn off events based on voltage changes of the battery by:
• determining a prior battery voltage average by calculating an average of a plurality of the oldest slots in the array;
• comparing each of a plurality of the most recent slots to the prior battery voltage average;
• and
• when a threshold number of the most recent slots are above the prior battery voltage average by at least an ignition turn on threshold, determining that an ignition turn on event has occurred.

A method of detecting ignition events of a vehicle using a telematics device having a controller, a wireless communication module, a power input terminal configured to couple to a battery of a vehicle to sense a voltage of the battery, and an ignition input terminal configured to couple to an ignition line of the vehicle, the method comprising:

• determining whether the ignition input terminal is coupled to an ignition line of the vehicle;
• when the ignition input terminal is coupled to an ignition line of the vehicle, determining ignition turn on and ignition turn off events by detecting voltage changes on the ignition line;
• and
• when the ignition input terminal is not coupled to an ignition line of the vehicle, sensing a voltage of a battery of the vehicle to determine ignition turn on and turn off events based on voltage changes of the battery by:
• repeatedly sensing a voltage sample of the battery after a time period, and storing the sensed voltages in slots of a moving array, the moving array including 20 slots, and each slot including an average of eight voltage samples taken at 250 millisecond intervals;
• determining a prior battery voltage average by calculating an average of a plurality of the oldest slots in the array;
• comparing each of a plurality of the most recent slots to the prior battery voltage average;
• when a threshold number of the most recent slots are above the prior battery voltage average by at least an ignition turn on threshold, determining that an ignition turn on event has occurred;
• and
• when a threshold number of the most recent slots are below the prior battery voltage average by at least an ignition turn off threshold, determining that an ignition turn off event has occurred;
• wherein the prior battery voltage average is an average of the four oldest slots, the plurality of most recent slots includes the most recent six slots, and the threshold number of the most recent slots is at least four slots.